function numberOnly(myfield, e) {
    var key,keychar;
    if (window.event) {
        key = window.event.keyCode
    }
    else if (e) {
        key = e.which
    }
    else {
        return true
    }
    keychar = String.fromCharCode(key);
    if ((key == null) || (key == 0) || (key == 8) || (key == 9) || (key == 13) || (key == 27)) {
        return true
    }
    else if (("0123456789").indexOf(keychar) > -1) {
        return true
    }
    return false;
}